SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7d1b5b7d2a0cdf091a5261e52bfe8f31bcedb7b021d37b48dad0d0e3d214e4a' 
  AND token = 'tBtoWuxCjrl+5M5YvoW5zPnuL9RYnGKcBrki9lveH9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}